1 /* SPDX-License-Identifier: BSD-2-Clause */ 2 /* 3 * Privilege Separation for dhcpcd 4 * Copyright (c) 2006-2020 Roy Marples <roy@marples.name> 5 * All rights reserved 6 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #ifndef PRIVSEP_H 30 #define PRIVSEP_H 31 32 //#define PRIVSEP_DEBUG 33 34 /* Start flags */ 35 #define PSF_DROPPRIVS 0x01 36 37 /* Protocols */ 38 #define PS_BOOTP 0x0001 39 #define PS_ND 0x0002 40 #define PS_DHCP6 0x0003 41 #define PS_BPF_BOOTP 0x0004 42 #define PS_BPF_ARP 0x0005 43 44 /* Generic commands */ 45 #define PS_IOCTL 0x0010 46 #define PS_ROUTE 0x0011 /* Also used for NETLINK */ 47 #define PS_SCRIPT 0x0012 48 #define PS_UNLINK 0x0013 49 #define PS_READFILE 0x0014 50 #define PS_WRITEFILE 0x0015 51 #define PS_FILEMTIME 0x0016 52 #define PS_AUTH_MONORDM 0x0017 53 54 /* BSD Commands */ 55 #define PS_IOCTLLINK 0x0101 56 #define PS_IOCTL6 0x0102 57 #define PS_IOCTLINDIRECT 0x0103 58 #define PS_IP6FORWARDING 0x0104 59 #define PS_GETIFADDRS 0x0105 60 61 /* Dev Commands */ 62 #define PS_DEV_LISTENING 0x0201 63 #define PS_DEV_INITTED 0x0202 64 #define PS_DEV_IFCMD 0x0203 65 66 /* Dev Interface Commands (via flags) */ 67 #define PS_DEV_IFADDED 0x0001 68 #define PS_DEV_IFREMOVED 0x0002 69 #define PS_DEV_IFUPDATED 0x0003 70 71 /* Process commands */ 72 #define PS_START 0x4000 73 #define PS_STOP 0x8000 74 75 /* Max INET message size + meta data for IPC */ 76 #define PS_BUFLEN ((64 * 1024) + \ 77 sizeof(struct ps_msghdr) + \ 78 sizeof(struct msghdr) + \ 79 CMSG_SPACE(sizeof(struct in6_pktinfo) + \ 80 sizeof(int))) 81 82 /* Handy macro to work out if in the privsep engine or not. */ 83 #define IN_PRIVSEP(ctx) \ 84 ((ctx)->options & DHCPCD_PRIVSEP) 85 #define IN_PRIVSEP_SE(ctx) \ 86 (((ctx)->options & (DHCPCD_PRIVSEP | DHCPCD_FORKED)) == DHCPCD_PRIVSEP) 87 88 #include "config.h" 89 #include "arp.h" 90 #include "dhcp.h" 91 #include "dhcpcd.h" 92 93 struct ps_addr { 94 sa_family_t psa_family; 95 uint8_t psa_pad[4 - sizeof(sa_family_t)]; 96 union { 97 struct in_addr psau_in_addr; 98 struct in6_addr psau_in6_addr; 99 } psa_u; 100 #define psa_in_addr psa_u.psau_in_addr 101 #define psa_in6_addr psa_u.psau_in6_addr 102 }; 103 104 /* Uniquely identify a process */ 105 struct ps_id { 106 struct ps_addr psi_addr; 107 unsigned int psi_ifindex; 108 uint16_t psi_cmd; 109 uint8_t psi_pad[2]; 110 }; 111 112 struct ps_msghdr { 113 uint16_t ps_cmd; 114 uint8_t ps_pad[sizeof(unsigned long) - sizeof(uint16_t)]; 115 unsigned long ps_flags; 116 struct ps_id ps_id; 117 socklen_t ps_namelen; 118 socklen_t ps_controllen; 119 uint8_t ps_pad2[sizeof(size_t) - sizeof(socklen_t)]; 120 size_t ps_datalen; 121 }; 122 123 struct ps_msg { 124 struct ps_msghdr psm_hdr; 125 uint8_t psm_data[PS_BUFLEN]; 126 }; 127 128 struct bpf; 129 struct ps_process { 130 TAILQ_ENTRY(ps_process) next; 131 struct dhcpcd_ctx *psp_ctx; 132 struct ps_id psp_id; 133 pid_t psp_pid; 134 int psp_fd; 135 int psp_work_fd; 136 unsigned int psp_ifindex; 137 char psp_ifname[IF_NAMESIZE]; 138 uint16_t psp_proto; 139 const char *psp_protostr; 140 141 #ifdef INET 142 int (*psp_filter)(const struct bpf *, const struct in_addr *); 143 struct interface psp_ifp; /* Move BPF gubbins elsewhere */ 144 struct bpf *psp_bpf; 145 #endif 146 }; 147 TAILQ_HEAD(ps_process_head, ps_process); 148 149 #include "privsep-inet.h" 150 #include "privsep-root.h" 151 #ifdef INET 152 #include "privsep-bpf.h" 153 #endif 154 155 int ps_init(struct dhcpcd_ctx *); 156 int ps_dropprivs(struct dhcpcd_ctx *); 157 int ps_start(struct dhcpcd_ctx *); 158 int ps_stop(struct dhcpcd_ctx *); 159 160 int ps_unrollmsg(struct msghdr *, struct ps_msghdr *, const void *, size_t); 161 ssize_t ps_sendpsmmsg(struct dhcpcd_ctx *, int, 162 struct ps_msghdr *, const struct msghdr *); 163 ssize_t ps_sendpsmdata(struct dhcpcd_ctx *, int, 164 struct ps_msghdr *, const void *, size_t); 165 ssize_t ps_sendmsg(struct dhcpcd_ctx *, int, uint16_t, unsigned long, 166 const struct msghdr *); 167 ssize_t ps_sendcmd(struct dhcpcd_ctx *, int, uint16_t, unsigned long, 168 const void *data, size_t len); 169 ssize_t ps_recvmsg(struct dhcpcd_ctx *, int, uint16_t, int); 170 ssize_t ps_recvpsmsg(struct dhcpcd_ctx *, int, 171 ssize_t (*callback)(void *, struct ps_msghdr *, struct msghdr *), void *); 172 173 /* Internal privsep functions. */ 174 pid_t ps_dostart(struct dhcpcd_ctx * ctx, 175 pid_t *priv_pid, int *priv_fd, 176 void (*recv_msg)(void *), void (*recv_unpriv_msg), 177 void *recv_ctx, int (*callback)(void *), void (*)(int, void *), 178 unsigned int); 179 int ps_dostop(struct dhcpcd_ctx *ctx, pid_t *pid, int *fd); 180 181 struct ps_process *ps_findprocess(struct dhcpcd_ctx *, struct ps_id *); 182 struct ps_process *ps_newprocess(struct dhcpcd_ctx *, struct ps_id *); 183 void ps_freeprocess(struct ps_process *); 184 void ps_freeprocesses(struct dhcpcd_ctx *, struct ps_process *); 185 #endif 186